How do I help my friend?

My friend is in a really miserable marriage. They lead separate lives mostly; but he is vile to her. She naturally snaps back. He has managed to get her to think everything is her fault. (she is holding everything together at the moment, family and house and money wise as he does nothing).

She wants to leave but her dc (teenagers) have told her she would be very selfish to.

She doesn't want to hurt them. And so she is staying. But is just in a state.

We have managed to convince her that the practicalities of money etc would be ok if she left.

How else can we support her and makes sure she knows we are there for her whether she leaves or not? She is very proud.

I am not sure how it came about. Two are still at home and say that yes they want to continue how things are even though they know she's unhappy. I have pointed out that they probably do because they don't know any different. But she's adamant that the best thing for them is to stay so she has to. I certainly don't want to try and persuade her to leave. But I do want to support her. How can I? Apart from giving the dc a bloody good talking to?